Field
The present disclosure relates generally to energy storage devices, and more particularly to metal-ion battery technology and the like.
Background
Owing in part to their relatively high energy densities, light weight, and potential for long lifetimes, advanced metal-ion batteries such as lithium-ion (Li-ion) batteries are desirable for a wide range of consumer electronics. However, despite their increasing commercial prevalence, further development of these batteries is needed, particularly for potential applications in low- or zero-emission hybrid-electrical or fully-electrical vehicles, consumer electronics, energy-efficient cargo ships and locomotives, aerospace applications, and power grids.
Materials that offer high capacity for such batteries include conversion-type electrodes (e.g., metal fluorides, sulfides, oxides, nitrides, phosphides and hydrides and others for Li-ion batteries), alloying-type electrodes (e.g., silicon, germanium, tin, lead, antimony, magnesium and others for Li-ion batteries) and others. The majority of such materials suffer from several limitations for various metal-ion battery chemistries, including: (i) low electrical conductivity, which limits their utilization and both energy and power characteristics in batteries; (ii) low ionic conductivity, which limits their utilization and both energy and power characteristics in batteries; (iii) volume changes during metal ion insertion/extraction, which may cause mechanical and electrical degradation in the electrodes and (particularly in the case of anode materials) degradation in the solid-electrolyte interphase (SEI) during battery operation; and (iv) changes in the chemistry of their surfaces, which may weaken the strength of (or even break) the particle-binder interface, leading to electrode and battery degradation.
Decreasing particle size decreases the ion diffusion distance, and offers one approach to addressing the low ionic conductivity limitation. However, nanopowders suffer from high electrical resistance caused by the multiple, highly resistive point contacts formed between the individual particles. In addition, small particle size increases the specific surface area available for undesirable electrochemical side reactions. Furthermore, simply decreasing the particle size does not address and may in some cases exacerbate other limitations of such materials, such as volume changes and changes in the external surface area of the particles, as well as weakening of the particle-binder interfaces.
Certain high capacity materials, such as sulfur (S), additionally suffer from the dissolution of intermediate reaction products (e.g., metal polysulfides) in the battery electrolyte, which further contributes to their degradation. Although sulfur incorporation into porous carbons via melt-infiltration has been shown to reduce dissolution and increase electrical conductivity of S-based cathodes, such techniques are narrowly tailored to a limited set of materials with low melting points like sulfur (about 115° C.) and to a limited set of producible structures (e.g., conformal coatings).
Accordingly, there remains a need for improved batteries, components, and other related materials and manufacturing processes.